Other intonation methods

Traditionally fretted instruments are only intonated by comparison of the harmonic at the middle of the string with the note on the 12'th fret.

On electric instruments each string is most often adjustable at the bridge. Here you can achieve decent intonation because the strings are thinner than on acoustic instruments. I dare say that acoustic guitars generally intonate very bad. Most often well enough seems to be a slanting of the bridge to make the bass strings somewhat longer than the treble strings. In some exceptional cases the thickest, non wound string is extended a bit longer in the bridge. Add to that that thicker strings, due to greater stiffness and less elasticity, are more sensitive to intonation errors than thin strings.

I have found a hand full of other intonation methods where the strings are compensated in both the nut and the bridge. These methods improves intonation, but can never achieve perfect results. All methods have in common that the distance between the nut and the first fret is shortened. The reason that these methods can never achieve perfect results is that the faults have not been analyzed properly. These methods are based on guessing.

A few of the methods use "offsets". Offsets are deviations from the equal temperament. One should intonate the strings at the bridge so and so many cents false. For optimal result you ought to buy a special electronic tuner so you can tune the open strings so and so many cents false. By offsets they try to hide the remaining faults after an insufficient intonation. This is pure guesswork.

Another method is based on a precompensated nut. The errors in the nut depend upon how deep the string grooves in the nut are cut and on both the stiffness and elasticity of the strings that happens to be on that particular instrument. Therefore it is impossible to make a correctly compensated nut in advance. As said, pure guesswork.

Compensations in both nut and bridge has to be individually made for each instrument and each string. Perfect results can never be achieved by generic methods.

In both the nut and the bridge there are two faults. Both faults are depending on what type (nylon, steel, wound or unwound) and what dimension of strings are used. The fastening faults depends on the stiffness of the string. The string height faults depends on the elasticity and the height of the string. In the bridge the faults are acting in the same direction, but in the nut they act in opposite directions. The dominating fault in the nut, determines the direction of the nut compensation. (It may occur that the distance to the first fret has to be made longer.)

Actually there is another method that could have given correct results - if it had been performed individually for each instrument: Click here

By bending the frets you can intonate to any temperament, but it seems to be an awkward way to achieve the equal temperament. Note that for other temperaments than the equal, you can't alter the tuning (e.g. drop-D or DADGAD) - as all notes on an altered string will be located to other frets. Also you can't adjust the intonation if you would like to alter string gauges or string height. Intonation at the nut and bridge is easy to adjust. I don't think these guys will manage to intonate a 12-string guitar. I do.

But take a good look at the picture of their equal tempered guitar. The bending of the frets gives a splendid graphical picture of how badly an electric guitar intonates. On an acoustic guitar, which has heavier strings and higher action, the frets require to be bent a lot more. As you see the faults are big. No wonder there is tuning problems!